Small digital cameras have become so inexpensive as to be offered on a wide range of portable and wearable devices from watches, to helmets, to computing tablets, to media players to cellular telephones of all kinds. These cameras are particularly convenient for taking video of high action scenes where a larger camera is impractical or intrusive. For professional video, the camera is usually mounted to a stable platform ranging from a simple tripod, to a tracked rail dolly, jib, or crane. Some of these platforms have stabilizers to keep the camera level and aimed as it is being moved and even to counter quick motions and jitter. When the camera is handheld, however, the photographer may not be able to provide a stable platform. Similarly a camera mounted to a helmet, vehicle, or other moving platform will be subject to movement and jitter as well, unless it is stabilized.
Stabilizers are normally large, heavy, and delicate, so video stabilization processing techniques have been developed. These techniques try to remove unwanted motion after the video is captured. The techniques also try to avoid removing wanted motion. On the one hand, the photographer's hand might shake or the bicycle rider may hit a bump. On the other hand, the photographer may sweep the camera across a scene, or move to view a different subject. For action sequences, there can be a great amount of motion as the camera experiences the action with the photographer. One common video stabilization technique is to apply a low-pass filter, such as a Gaussian filter, to the images of a video sequence. This filter tries to isolate fast (or high frequency) movements from slow movements and then compensate only for the fast movements. In principle, the movement from a shaky hand is removed while the movement from panning across a scene or moving to a different subject in the scene is not removed.